The possibility that ethanol-induced alterations in attention/vigilance contributes to an increase in accidents and lost productivity in the workplace is an important area of concern in today's society. This research project is based upon the following hypotheses: the effect of ethanol on safety and productivity is at least partly a result of drug- induced alterations in vigilance or attention, the effect of ethanol on vigilance is proportional to the length of time that the subject is required to remain vigilant and inversely proportional to the lack of predictability and the frequency of the signal presentation, the effect of ethanol on vigilance is magnified in the presence of a distracting task, and the finally, the effect of ethanol is altered by changing the cost: benefit ratio to the subject or reporting/or failing to report a signal presentation. Vigilance will be monitored by evaluating the ability of subjects to detect a brief stimulus change and to respond accordingly. To test the stated hypotheses, both the frequency and predictability of the signal presentation will be systematically changed, the relationship between the reporting of a signal presentation and the presentation of food will be changed by altering the schedule of reinforcement, the cost of reporting or failing to report a signal presentation will be examined punishing incorrect responses and false alarms with a mild electric shock or by the postponement of future signal presentations, and the influence of a distracting task will be examined by training the subjects to respond upon one response lever/key for food while simultaneously remaining vigilant to the presentation of a signal and responding upon a different lever/key for food following signal presentation. These studies will be conducted in both rats and pigeons trained to respond following a signal presentation under both a continuous trials and a discrete trials procedure. The continuous trials procedures was selected because it requires a more sustained attention than the discrete trials procedure and therefor may be more analogous to the workplace. However, a discrete trials procedure will also be studied because of the ability to incorporate trials which do not contain a signal. Consequently, the full power of signal detection analysis can be employed in the analysis of the data which is particularly important in addressing questions about change in the bias of responding. Finally, the utilization of the two procedures of the two procedures will permit a direct comparison of the results obtained under both procedures and should contribute significantly to the area of animal models of attention/vigilance. It is hoped that these studies will lead to a further understanding of the relationship between ethanol usage and vigilance and the impact of ethanol use on performance and safety in the workplace.